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1 BCM 3000 PRINCIPLES OF BIOCHEMISTRY (Semester 1 -2011/12)

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Presentation on theme: "1 BCM 3000 PRINCIPLES OF BIOCHEMISTRY (Semester 1 -2011/12)"— Presentation transcript:

1 1 BCM 3000 PRINCIPLES OF BIOCHEMISTRY (Semester /12)

2 2 Learning outcome (Objectives) ● Function and distribution. ● Characteristics of fatty acids-structure and chemical properties. ● Saturated and unsaturated fatty acids. ● Structures and properties of phospholipids, sphingolipids, waxes, terpenes and steroids. LIPID

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6 6 ???????

7 7 DEFINITION : General definition – all compounds called fat and oils TECHNICAL DEFINITION Fat : Triglycerides in the form of solids at room temperature Oils : Triglycerides which are liquid at room temperature LIPID

8 8 Any natural compound which is insoluble or nearly insoluble in water but soluble in non- polar solvents – a.Chloroform b.CS 2 c.Ether d.warm or e.hot ethanol General Definition

9 9 i.Structural functions - Components of membranes ii.Storage forms of carbon and energy iii.precursor for major compounds – e.g. hormones. iv.Insulators - thermal, electrical or physical shock v.protective coatings – prevent infections, loss or addition of compounds vi.Regulators - as vitamins & hormones FUNCTIONS Lipids are widely distributed in both animal and plant systems and perform a wide variety of functions

10 10 1.SIMPLE LIPIDS Fatty acid esters (Acid + alcohol  ester) 2. COMPPOUND LIPID Fatty acid + alcohol + OTHER COMPOUNDS CLASSIFICATION

11 11 LIPIDCOMPONENTS Acyglycerols (Glycerol + Fatty acids) = WaxesAlcohol + fatty acids SIMPLE LIPIDS Esters ???

12 12 4 types of Compound lipid i.Phosphoglycerides ii.Sphingolipids iii.Cerebrosides iv.Gangliosides COMPOUND LIPIDS

13 13 LIPIDCOMPONENTS iPhosphoglycerides Glycerol + Fatty acid +HPO satu OHR iiSphingolipids Sphingosine + Fatty acid + HPO Choline iiiCerebrosides Sphingosine +Fatty acid + Simple sugar ivGangliosides Sphingosine + Fatty acid Simple sugar (Including sialic acid) COMPOUND LIPID

14 14 i & ii = Phospholipid - presence of phosphate ii, iii & iv = Sphingolipids - presence of Sphingosine iii & iv = glycolipid - presence of carbohydrate

15 15 GLYCEROL – Trihydroxy alcohol

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17 17 ● Long chain aliphatic carboxylic acids- contains carboxyl group – polar head and `tail’ containing hydrocarbon chain Long chain aliphatic carboxylic acids- contains carboxyl group – polar head and `tail’ containing hydrocarbon chain ● Amphiphilic compounds – hydrophilic head and hydrophobic tail Amphiphilic compounds – hydrophilic head and hydrophobic tail ● COOH can be ionised COOH can be ionised ● Monocarboxyilic acids – linear hydrocarbon chain, even carbon numbers – between C 12 -C 20 Monocarboxyilic acids – linear hydrocarbon chain, even carbon numbers – between C 12 -C 20 ● Short, longer, branched, cyclic and odd numbers also exist BUT not many Short, longer, branched, cyclic and odd numbers also exist BUT not many FATTY ACIDS

18 18 Octadenic acid

19 19 2 TYPES 1.Saturated Fatty acids 2.Unsaturated Fatty acids FATTY ACIDS

20 20 Fats ● mostly from animal sources, ● have all single bonds between the carbons in their fatty acid tails, thus all the carbons are also bonded to the maximum number of hydrogens possible. ● saturated fats ● The hydrocarbon chains in these fatty acids are, thus, fairly straight and can pack closely together, making these fats solid at room temperature. Structure of Fatty Acids - Saturated

21 21 Saturated fatty acid –e.g. 1.palmitic acid (CH 3 (CH 2 ) 14 COOH) (16C) & 2.Stearic acid (CH 3 (CH 2 ) 16 COOH)

22 22 Saturated Fatty Acids

23 23 ● Unsaturation normally at - C 18 & C 20 – double bond separated by methylene group -CH = CH - CH 2 - CH = CH ● Double bonds = cis configurationcis configuration ● Unsaturated fatty acid - oleic (18:1), Linoleic (18:2), Linolenic (18:3) & arachidonic (18:4) Structure of Fatty Acids - Unsaturated

24 24 ● C=C double bond arranged in two ways ● In cis bonds, the two pieces of the carbon chain on either side of the double bond are either both “up” or both “down,” such that both are on the same side of the moleculecis bonds ● In trans bonds, the two pieces of the molecule are on opposite sides of the double bond, that is, one “up” and one “down” across from each othertrans bonds ● Naturally-occurring unsaturated vegetable oils have almost all cis bonds, but using oil for frying causes some of the cis bonds to convert to trans bonds Unsaturated fatty acids

25 25 TRANS CIS

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27 27 Unsaturated Fatty Acids

28 28 ● fatty acids with trans bonds are carcinogenic, or cancer-causing. carcinogenic ● containing products such as margarine are quite high,

29 29 ● mostly from plant sources, ● have some double bonds between some of the carbons in the hydrocarbon tail, causing bends or “kinks” in the shape of the molecules. ● Because some of the carbons share double bonds, they’re not bonded to as many hydrogens ● oils are called unsaturated fats. ● kinks  unsaturated fats can’t pack as closely together, making them liquid at room temperature Oils

30 30 CIS TRANS

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32 32 ●Vegetable oils often contain high proportions of polyunsaturated and mono-unsaturated fats (oils)  liquids at room temperature. ●You can "harden" (raise the melting point of) the oil by hydrogenating it in the presence of a nickel catalyst. Making margarine

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35 35 2 GROUPS i.Neutral acyglycerols (e.g. Triacylglycerol) ii.Waxes Acyglycerols = glyceride = a tryhydroxy alcohol estertryhydroxy alcohol ester = glycerol + fatty acid (3 different fatty acids) =can be esterified SIMPLE LIPIDS

36 36 GlycerolGlycerol = trihydroxy alcohol

37 37 TRIACYGLYCEROLS

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42 42 ● Triacylglycerol – the most abundant ● No ionic groups -  neutral lipids ● Triacylglycerol = neutral fats neutral oils (liquid)

43 43 I.Adipose tissues - `fat depots' = storage forms of carbon and energy`' II.Transport - chylomicrons - = lipoprotein – fatty acids are transported through lymphatic system and blood  tissue adipose tissues and other organs III.`Physical protection' - e.g. temperature. FUNCTIONS IN ANIMALS

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45 45 

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47 47 ● Also an ester - alcohol & fatty acid = very long hydrocarbon chain – commercial application ● hairs, skin, leaves, fruits WAXES

48 48 Asid Oleic WAXES

49 49 1.Hydrogenation CHEMICAL CHARACTERISTICS OF TRYACYLGLYCEROL (Reactions of Triacylglycerol)

50 50 Double bonds in vegetable oils can be hydrogenated  oils become solids – can control - e.g.. peanut butter - crunchy, creamycreamy HYDROGENATION PROCESS

51 51 Other halides - Iodine(I 2 ), Chlorides (Cl 2 ) 2.Halogenation – Addition of halogens

52 52 ● Saturated fatty acid – iodine number = 0 ● Oleic acid - 90, ● linoleic- 181, ● Linolenic = 274

53 53 ● Animal fat-iodine number is low ● Vegetable oils – iodine number is high

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55 55 (i.)Base Hydrolysis  Fatty acid + Glycerol or Salts of fatty acid + Glycerol ● inside cells – by enzymes (lipase) – very specific for ester bonds – products are glycerol + fatty acidslipase ● Non-enzymatic- with alkali (base)  salts of fatty acid + Glycerol ● salts of fatty acids = soap Base Hydrolysis = SAPONIFICATION 3.Hydrolysis

56 56 ● The reaction of triacylglycerol with base (alkali) - e.g.. NaOH, KOH ● Triacylglycerol – presence of strong ester bond ● Ester bond can be hydrolyzed by base  salts of fatty acid + glycerol Salts = soap – react as a soap/detergent SAPONIFICATION

57 57 Saponification reaction (Base Hydrolysis)

58 58 If R= palmitic acid  Sodium palmitate If R’= oleic acid  Sodium oleate R”= stearic acid  Sodium stearate

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60 60 Detergent? =`surface active agents' – lower surface tension of surface of water H 2 O = `poor cleansing agent - Y?  Because the molecule is very polar and tend to stick to each other – therefore cannot enter non-polar areas like grease, oil, dirt

61 61 i.Hydrophobic tails enters grease layersgrease layers ii.Hydrophilic heads come into contact with aqueous layer  separate grease layer from the surface iii.Small grease globules form- `pincushion‘`pincushion‘ iv.These globules have similar charges - therefore cannot go near each other – can wash HOW DOES A DETERGENT WORK ??

62 62 Grease Water

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65 65 ● strong hydrophilic and hydrophobic tailhydrophobic ● Ordinary soap = mixture of potassium salts of fatty acids from saponification - not a very good detergent ? e.g. Sodium palmitateSodium palmitate ● The negative ions in soap forms precipitate with metals in hard water (?)  use syndets = soluble in water ● e.g.. SDS = Sodium dodecil sulfateSodium dodecil sulfate Best detergent

66 66 Head - Polar (hidrofilik) Ekor- Tak polar (Hidrofobik)

67 67 Carboxylic acids (ii).Acid Hydrolysis

68 68 Expose triacylglycerol to warm and moist air  rancid (tengik) 2 reactions take place 1.Ester hydrolysis 2.Oxidation of the double bonds ● Hydrolysis - water (inside the lipid) + enzyme (bacteria in the air) ● Oxidation-by O 2 on the side chain of triacylglycerol  short chain fatty acids – rancid (tengik) 4. RANCIDITY

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70 70 Phosphoglycerides = Phosphoglycerol i.e. they are derived from glycerol Fatty acids Phosphate group Glycerol Phosphoglycerides

71 71 Phosphoglycerol = Phosphoglyceride other alcohols

72 72 Glycerol (Trihydroxyglycerol) Phosphatidic acid (Glycerol + 2 fatty acids + Phosphate) Phosphoglyceride (Phosphoglycerol) (Glycerol + 2 fatty acids + Phosphate + other group e.g.. alcohol)

73 73 All phosphoglycerides are Phospholipids!!!!

74 74 Phosphoglycerides can be further esterified to form  other lipids i.Phosphatidylcholine ( choline ester)Phosphatidylcholine ii.Phosphatidylethanolamine (ethanolamine)Phosphatidylethanolamine iii.Phosphatidylserine (serine)Phosphatidylserine  All are important components of membranes membranes

75 75 Asid lemak Phosphate

76 76 Phosphatidylethanolamine

77 77 Phosphatidylethanolamine

78 78 Phosphatidylserine

79 79 Membrane

80 80 ● No glycerol – replaced with amine alcohol = Sphingosine Sphingosine ● Number of carbon atoms –varies ● The simplest = ceramides = Fatty acid + sphingosine through amino group via amide bondceramides ● Sphingomyelin – an example of sphingolipid - 1 o alcohol esterified to phosphate Sphingomyelin  amino alcohol (= choline) Found in nerve membranes and brain SPHINGOLIPID

81 81 CH  CH(CH 2 ) 12 CH 3  CHOH  CH NH 2  CH 2 OH H 2 C  OH  H 2 C  OH  H 2 C  OH Sphingosine Glycerol SPHINGOLIPID 1.What is the main structure for sphingolipid? Sphingosine 2.Draw the structure of sphingosine 3.Draw the structure of glycerol and compare between the two

82 82 ● No glycerol – replaced with amine alcohol = Sphingosine Sphingosine ● Number of carbon atoms –varies ● The simplest = ceramides = Fatty acid + sphingosine through amino group via amide bondceramides ● Sphingomyelin – an example of sphingolipid - 1 o alcohol esterified to phosphate Sphingomyelin  amino alcohol (= choline) Found in nerve membranes and brain SPHINGOLIPID

83 83 CERAMIDE

84 84 Phosphate Choline

85 85 ● When a carbohydrate is attached to OH- via glycosidic bond ● Seb. induk = ceramide (sphingolipid) + CHOceramide ● Cerebroside - CHO = galactose ●  glucocerebrosideglucocerebroside ● GANGLIOSIDE – ALSO contains oligosaccharide + sialic acid GLYCOLIPID

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87 87 ● A heterogeneous group ● Derived from fatty acids ● steroids, prostaglandin, leukotriene, carotenoids, vitamin STEROID All organisms – similar basic structure – fused ring= perhydrocylopentanophenanthrene DERIVED LIPIDS

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90 90 i.Hydrocarbon chain (C18-C20) at C17C17 ii.Hydroxyl group (OH) at C3 ● Main example = CHOLESTEROL – structural component of membrane % lipid membrane. Rigid ● Precursor of bile, sex hormones, vit. D. ● Role in atherosclerosis STEROL

91 91 Hydrocarbon chain at C17 OH at C3 CHOLESTEROL

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93 93 ● Lipid derived from isoprene ● Term used for all compounds synthesized from the precursor isoprene  cholesterol, bile acid, steroid, lipid soluble vitamins = terpene terpene ● Oils from turpentine (pine tree extracts) ● formula C 10 H 15 ● > 15 carbon atom also found - `multiples of 5 ● Also in other plants TERPENE

94 94 Terpene with 20 carbon atoms - vit. A - 40 carbon atoms -  - carotene  - carotene EXAMPLES: 1.monoterpene - Limonene - `odor' lemon Limonene 2.Diterpene - Gibberrelic acid – plant hormone 3.Triterpene - Squalene – Cholesterol precursor 4.Tetraterpene - Lycopene - tomato pigmentsLycopene TERPENE

95 95 TERPENE

96 96 TERPENE

97 97 TERPENE

98 98 BCM 3000 PRINCIPLES OF BIOCHEMISTRY (Semester /12)

99 99 ● Lipid – not soluble in water but can still be found in aqueous environment ● behavior in water important to understand the phenomena ● A lot of lipids are amphiphyllic = having  hydrophobic part (hydrocarbon chain)  polar (ionic) part LIPID BEHAVIOUR IN WATER

100 100 When lipid is dispersed in water, the hydrophobic part will segregate from the solvent through `self-aggregation' – form a.micelles – which are dispersed in watermicelles b.monolayers ( aggregate – boundary H 2 O: air

101 101 MONOLAYER MICELLES

102 102 The tendency for hydrocarbon chains to distance away from polar solvents gives rise to = HYDROPHOBIC EFFECT ● Most lipids will form micelles – spheres, ellipse, discs, cylinders ● Also can form vesicles – bilayer – hydrocarbon chains are opposite to each other  `hollow sphere'bilayer

103 103 Micelle Bilayer Vesicles

104 104 BILAYER

105 105 CholesterolCholesterol does not form micelles ??  Not amphiphatic compounds  Structure – flat fused ring -  solid –difficult to form micelles Can form mixed micelle with amphiphatic lipids mixed micelles – with amphiphatic lipids

106 106 Bile acids serve many functions. ● They aid in fat absorption They aid in fat absorption ● Bile acids are produced from cholesterol in the liver. Bile acids are produced from cholesterol in the liver. ● Cholesterol is converted to the carboxylic acids cholic and chenodeoxycholic acid, which are the primary bile acids in most species. Cholesterol is converted to the carboxylic acids cholic and chenodeoxycholic acid, which are the primary bile acids in most species. ● The liver conjugates the acids to either glycine or taurine and subsequently secrets them into the bile. The liver conjugates the acids to either glycine or taurine and subsequently secrets them into the bile. ● The gall bladder serves to store bile acids until contraction associated with feeding The gall bladder serves to store bile acids until contraction associated with feeding BILE ACID AND BILE SALTS

107 107 GlycineTaurine

108 108  Particles that contain lipid and protein  bonds = not (non-covalent) bonds  Function – In blood plasma – to transport triacylglycerol and cholesterol STRUCTURE - form `micelle like particles' - i. core – non-polar triacylglycerol ii.Surrounded by a layer of amphiphilic protein, phospholipid and cholesterol LIPOPROTEIN

109 109 Various categories – depending on the functions i.CHYLOMICRON – Carries exogenous triacylglycerols & cholesterol (from diet) from intestine to the tissues.CHYLOMICRON ii.LDL, IDL & LDL – group of related particles which carry endogenous triacylglycerols & cholesterol (produced internally) from the liver to tissuesLDL, IDL & LDL NB:liver can synthesize triacylglycerol from excess carbohydrate

110 110 CHYLOMICRON

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112 112 Cholesterol Cholesterol – ● Important component of membrane – can be supplied from the outside or internally (if not enough) ● How obtained externally ? – ENDOCYTOSIS – Through reaction of specific receptors = LDL receptor?ENDOCYTOSIS ● protein part of LDL tie up to R-LDL in the cell complex  `pinched off' = endocytosis LDL, CHOLESTEROL & ATHEROSCLEROSIS

113 113 ENDOCYTOSIS vs EXOCYTOSIS

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115 115 Protein – recycled – used in the cell Oversupply ? –  Synthesis of R-LDL inhibited  low LDL  cholesterol level in blood increases  deposited in the artery  heart disease; stroke HDL  Function opposite of LDL  Carries cholesterol from tissues - extract cholesterol from membrane – change to `cholesteryl esters - LCAT (Lecithin cholesterol transferase)  bile acids


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